1. Field of the Invention.
My invention relates to plumbing systems, and more particularly to backwater escape valves for such systems.
2. Description of the Prior Art.
A basic problem with residential and commercial plumbing systems is the back flow of sewage and drain water into the plumbing fixtures thereof; due, for example, to blockage or obstruction of the associated sewer lines. This problem is exacarbated when the particular residential or commercial plumbing system is that of a multiple-occupancy building, such as an apartment building, an office building, or other multi-unit structure having a large number of drain fixtures therein.
In order to provide access to blockages and obstructions, plumbing codes require commercial and residential plumbing systems to include cleanouts throughout the system.
Typically, a cleanout is comprised of a T-fitting in a drainpipe or sewer line and a threaded plug closing one arm of the T-fitting or closing the outer end of a length of pipe extending from said arm of said T-fitting to a point of relatively easy access, such as a point located outside the outer wall of the building served by the plumbing system and near ground level.
When blockage of a drainpipe or sewer connection occurs and drain water backs up to a sink or the like the threat of overflow can be eliminated by removing the threaded plug from a properly located cleanout which is connected to the drainpipe serving that sink.
U.S. Pat. No. 4,475,571 issued on Oct. 9, 1984, to Houston and Baker, addresses the problem of preventing the backflow of sewage from sewers into drain fixtures by providing a float valve adapted to automatically open the upper end of a vertical pipe extending from a sewer line to a point near the ground surface adjacent the building serviced by the plumbing system.
Such a float valve, however, because of its complexity, is subject to being rendered wholly or partly inoperative by the collection of solids carried by sewer backup.
Further, such float valves are not adapted for use with the now well-known horizontal cleanouts which project from the outer wall of the building serviced by the associated plumbing system at or near ground level.
Yet further, such float valves, because of their multiplicity of parts, etc., are more expensive than is desirable, and thus add to the cost of new plumbing systems.
It is believed that the documents listed immediately below contain information which is or might be considered to be material to the examination hereof.
______________________________________ U.S. Pat. No. Inventor ______________________________________ 168,517 J. Morrell 480,374 G. Seeback 1,763,562 J. Mulder 2,908,286 O. Hallstrom 4,700,732 R. Francisco 426,772 (Italy) B. Belati et al. ______________________________________
A copy of each of the above-listed documents is enclosed herewith.
The term "prior art" as used herein or in any statement made by or on behalf of applicant means only that any document or thing referred to as prior art bears, directly or inferentially, a date which is earlier than the effective filing date hereof.
No representation or admission is made that any of the above-listed documents is part of the prior art, or that no more pertinent information exists.